Valve



J. K. HELLER May 15, 1951 VALVE 5 Sheets-Sheet 1 Filed Jan. 19, 1946 INVENTOR. JOH/VK/7'ELLEQ ATTORNEY May 15, 1951 J. K. HELLER 2,552,785

VALVE Filed Jan. 19, 1946 5 Sheets-Sheet 5 INVENTOR. k/aH/v K. HELLER A TTOf/VEK Patented May 15, 1951 Gasair ation, San Francisco, Calif., a

v pt. I emanation of California Application January 19, 1946, Serial No. 642,187 25 claims. (01. 127- 129) This invention relates to snap-acting valves and particularly to snap-acting valves of the pressure loaded type for opening and closing one conduit to fluid ,flow therethrougnin response to changes in fluid pressure in another conduit.

It is a general object of the invention to provide an improved snap-acting valve of the pres: sure loaded type that is sensitive to relatively small changes in pressure in the pressure loading conduit and that will rapidly operate between fully open and fully closed positions.

Another object of the invention is to provid a snap-acting valve of the pressure loaded type that is capable of operating againsta high pressure in the conduit to be opened and closed in response to small variations in a relatively low pressure in the pressure loading conduit.

Another object of the invention is to provide a snap-acting valve of thepressure loaded type in which the range of variation in pressure in the pressure loading conduit required to actuate the valve may bereadily widened or narrowed and raised or lowered. V I

Another objectof the invention is to provide a snap-acting valve of the pressure loaded type in which the above mentioned adiustrnents may be made while the valve is in service without interrupting its operation.

Another object of the invention is to provide a pressure loaded, snap-acting valve that will. continue to operate for long periods of time precisely at the selected loading pressures for which it is set. 7

Another object of the invention is to ,provide a pressure loaded, snap-acting valve that is mechanically reliable and positive in itsaction.

Still other objects andadvantages of the invention will become apparent from the follow ing description of a preferred embodiment of the invention that has been selected for illustrative purposes and is shown in the accompanying drawings, in which:

Fig. l is a schematic fiow diagram of a gas mixing system in which a valve embodying the pres= ent invention may be advantageously employed;

Fig. 2 is a vertical, sectional view of a valve embodying the present invention and showing the valve actuating mechanism as it appears Fig. 5 is a vertical, sectional viewof the valve shown in Figs. 2 ;and taken as indicated by the line 5+5 in 'Fig. 2; and

. Fig. is n enl rg d ragmenta s tional view of a portion of the structure shown in Fig.3. Fig. 7 is a view similar to Fig. 2 of amodified 'm the inv n qa- Referring fir t, tQ a. a sch ma c o (l r gram is h w f r a m xi s s e dapte t c e to e ample und ed. m u i 2 as r ia ews r. rs ativ lvhish es u e m x ihs err tiia s lgc di rp q pn o m other gas and supplying the mixture at a lower res man. as ess tvoi r e ahmh i pli the n ed-Lea is. a. d io s tem l e t rant q nis 9 signed to rhaintainapressure Qof mixed-gas; in the s t t W 1. Y w... nl w th n a lectedrangein spite of a non-uni'f orm demand from the distribution ystem. In ni is igtm A n se. at gaseousbutaiieuna r higji pir s to b'iiiiiieki with air an fed at a ientitely row pressure, to areservbirthat in "u i t'ribution system "511 stations with a mixture able for fuel. Forthisp p system may comprise any suitable s'o' shown) of gaseous butane undei' p supplyingthe butane tissues a conduit n it a distributor l2 that a'cts both as and on? valve and as an output ressure 1* or of the pressure loaded at for rough ing the outgoing pressure. From the d tor I2, the but nefiqwstiid are shit 7 I pressure through a conduit l3; p era'bly h ng an interposed check valve shown) to; an aspirator typeof m xer I6. Within the mixer. the butane flows througli a nozzle ll andis mixed with air admitted 'thifougli an air inlet 18, including a check was i9. 7 The mixture of butane and air passes from th mixer l6 through a ventun tube 21 into a laies fr'voirtr sags tank 22, diiifing which passage the pressures; the gas mixture is dropped within a selected range to be maintained in the reservoir- 22; The vapor outlet pressure from the tor 12, when the distributor is in its 1 F dition, may be controlled by a regulated pres rd of butane gas supplied to the distributor through a conduit 23; the distributor being adapted to change to its off condition when the pressure in the conduit 23 is cut off. Suitable apparatus for supplying butane under pressure for this purpose to the distributor l2 through the conduit 23 may comprise a conventional form of pressure regulator 24 having its high pressure side connected to the high pressure vapor supply conduit through an intermediate conduit 26, and its low pressure side connected to and maintaininga constant pressure in the pressure loading conduit 23 through an intermediate conduit 2'! and through a pressure loaded, snapacting valve unit 28.

The function of the valve unit 28 is to maintain communication between the conduits 23 and 27 for holding the distributor [6 in its on condition until the mixed-gas pressure in the reservoir 22 reaches a pre-selected maximum" value, then to interrupt communication between the conduits 23 and 21 for permitting the distributor to change to its off condition, and then to restore communication between the conduits 23 and 21 for shifting the distributor back to its on condition when the pressure in the reservoir 22 has dropped to a pre-selected minimum. "To "enable the snap-acting valve unit 28 to perform this function, it is maintained-incommunication with the reservoir 22 by means jof an intermediate conduit 29. A valve unit constructed in accordance with the present invention is admirably adapted to perform the last described series of operations, and a preferred embodiment of such a valve will now be described to illustrate the invention and its mode of operation.

Referring first to Figs.- 2 to 4, and particularly to Fig. 2, the-valve unit illustrated therein comprises a housing that includes an upper hollow casting 3| and a lower'hollow casting 32. The upper casting 3| is generally cup-shaped and is provided with an open lower end terminating in an outwardly projecting annular flange 33. The lower casting 32 defines a generally cylindrical-upper 'cavity'having an open upper end terminating in an outwardly projecting, annular flange 34' adapted to register with the similar flange 33 f the upper casting, and also partially defines a generally cylindrical lower cavity communicating with the upper cavity and having an open lower end terminating in an outwardly projecting annular flange 36 (Fig. 4). The annularflanges'33 and 34 of the two castings 3i and 32 are secured together by .a series of bolts 31 with the marginal portion of a large, circular, flexible diaphragm 38 pierced by the bolts 31 and sandwiched between these flanges; and a closure disk 39,'having a slightly dished inner surface, is secured to the annular flange 36 by a'series of bolts 4| with the marginal portion of a small, circular, flexible diaphragm 42 pierced by the bolts 4| and sandwiched between the flange 36 and the marginal portion of the disk 39. Thus, the composite valve unit housing defines a large chamber divided into three superposed compartments by the two diaphragms 38 and 42. The two lower compartments 43 and 44 are'employed as sealed gas chambers for purposes described hereinafter, whereas the uppermost compartment 46 is'vented to the atmosphere and serves merely as as support and as a shield from dustpand dirt for the apparatus contained .therein. For greater clarity in the following description, therefore, the two lower compartments 43 and 44 will be respectively referred to .as upper and lower pressure compartj The valve per se, that is to be interposed between the conduits 21 and 23 leading from the pressure regulator 24 to the'distributor I2, is 7 contained within a hollow boss 53 integrally formed on the lower casting 32'and defining a generally. cylindrical valve chamber 54. An inlet port 56 for the valve chamber 54 is formed in a block or plug 51 that projects into a complementary-shaped aperture in the boss 53. The block 51 forms one end-wall of the valve chamber 54 and is secured in place by a number of cap screws58, or the like. The portion of the block 57 that projects into the hollow boss 53 seats against suitable sealing rings 59 and 60 to prevent gas leakage, and the inner end of this portion of the block 51 is provided with an integrally formed, annular, valve seat 62 that projects slightly into the valve chamber 54. The conduit 21 from the pressure regulator 24 may be connected to the valve inlet port 56 in any suitable manner for supplying gas under uniform pressure to the valve chamber 54. An outlet port 63 for the valve chamber 54 is formed in the lower casting 32 and extends downwardly throughia wall portion of the lower casting, through the'rnarginal portion of the small flexible diaphragm 42, and through a, boss 64 integrally formed on the closure disk 39. To assistin' aligning the flexible diaphragm 42 so it will not interrupt the outlet port 63, a short piece of brass tubing 66, or the like, adapted to fit snugly into a slightly enlarged portion 61' of the outlet port as and into the boss 64 on the closure disk, maybe passed through this diaphragm during assembly of the parts. The conduit 23 leading to the distributor [2 may be connected to the valve outlet port 63 at the boss 64 in any suitable manner for receiving gas under pressure from the valve chamber 54.

. A suitable, poppet type, movable valve element, generally designated 68, is mounted within the valve chamber 54 for movement into and out of engagement with the valve seat 62. The movable valve element 68 includes an integrally formed valve stem 69 that extends through the adjacent wall of the lower casting 32 and into the upper pressure compartment 43. Axial movement of the valve stem 69 is guided by a bushing II that is threaded into the lower easting 32 and that is provided with an integrally formed, annular, valve seat 12 projectin slightly into the valve chamber 54. The valve seat 12 is adapted to engage the movable valve element 68 When the valveris open in order to prevent leakage of gas from the valve chamber around the valve stem 69 into the upper pressure comelement 68 may comprise a generally cylindrical body portion 13, with which the valve stem 69 is integrally formed, the body portion being slightly tapered or chamfered adjacent the valve stem end thereof'so that it may be snapped into a cylindrical cap member 14 and retained snugly therein. The wall of the cap member II; is: similarly tapered at its open end and is provided (,6 at the opposite end thereof for retaining a.

cushioning disk ll of synthetic rubber, fibre board, or other material suitable to. effect slightly cushioned contact between the, movable valve element 68 and the valve seat 62 on the block.

51. The outer diameter of the flange H is made just enough smaller than the internal diameter of the valve chamber 54 so that the small flow of gas through the valve chamber from the .con-

duit 2'! to the conduit 23 when the valve is open may pass around th flange through the clearance space betweenit and the wall of the valve chamber. This clearance may be great enough to permit the necessary gas flow and still be small enough so that the pressure in the conduit 21 will force the movable valve element from the position shown in Fig. 3 to the position shown in Fig. 2 under conditions described hereinafter.

The bushing ll, in which the valve stem 69 is slidably mounted, is preferably provided with an internal bore for a portion of its length (as shown at 18) that makes a close sliding lit with the valve stem ea for maintaining its alignment, the remainder of the length of the bore being of larger diameter (as shown at 19). A port 80 is drilled into the bushing II and into communication with the portion of the bore of larger diameter to permit gas passing from the valve chamber 54 into the enlarged portion of the bore around the valve stem 69 to bleed freely into the upper pressure compartment 43 when the movable valve element 68 is out of contact with the valve seat I2 on the bushing II Inside the upper pressure compartment 43, a.

valve actuating lever BI is mounted on a shaft 82 that is rotatably supported at its opposite ends in a pair of female trunnions 83 (Fig. 5'), the trunnions being threaded through suitable apertures in the wall of the lower casting 32. The lever 8| may be press-fitted on the fulcrum shaft 82, is aligned with the valve stem 69, and is appropriately contoured along one side for bearing against the adjacent end of the valve stem. When pivoted in one direction, the lever 8| forces the movable valve element 68 into engagement with the valve seat 62. When pivoted in the opposite direction, the lever 8I permits the movable valve element to be forced into engagement with the valve seat 12 on the bushing ll by the pressure supplied through the conduit 21. A projecting lower end 84 of the lever 8| functions as a stop by contacting the lower casting 32 when the movable valve element 68 is seated against the valve seat I2 and the lever has moved slightly out of contact with the valve stem 69. The other end of the lever BI and one side thereof opposite the side contacted by the valve stem 69 are appropriately contoured to provide two angularl-y disposed, intersecting. cam surfaces 85 and 96 along which a lever actuating roller 8'! may roll in a manner described hereinafter.

Movement of the roller 31 along the cam surfaces 85 and 86 is controlled by movement of the large flexible diaphragm 38, an interconnecting linkage housed within the upper gas chamber 43 being provided to effect such control. The

linkage connection to the large diaphragm 38:

includes a diaphragm stud having a hexagonal head 9.I that bears against the lower surface of the. diaphragm and a hollow upper shank 92 that projects from the head 9| through the center of the diaphragm. and through the center of a diaphragm plate 93 that is secured against the upper surface of the diaphragm for stiffening purposes. Above the diaphragm plate 93, the upper shank 92 is threaded into a nut 94, a standard lock washer 95: being employed on the shank 92 between the diaphragm plate 93 and: the nut 94. The diaphragm stud is also provided with a lower shank 96 that is threaded into a diaphragm yoke 91 having a pair of spacedapart, downwardly-extending arms 98. At their lower ends, the arms 98' of the yoke 91 are joined by a cross-brace 98a and are respectively pivotally connected to a pair of parallel arms 99 of a lever Iiflil by means of a pair of pins ml. The lever I00 is generally the shape of a reversed L as viewed in Fig. 2 and as viewed in Fig. 4, resembles an inverted Y with the two arms of the Y joined by a cross-brace 99a. The fulcrum for the lever is a shaft I92 that may pass freely through both arms 99 of the lever and is rotatably supported at its opposite ends (in the same manner as the shaft 82) in a pair of female trunnions 33 (Fig. 4) threaded into suitable apertures in the lower casting 32. At its upper end the lever IE9 is pivotally connected to the two legs of an H-shaped link I96 by means of a pin I01, the upper end of the lever I00 being disposed between the two legs of the link I06. Atthe opposite end of the link I96, the roller 31 is rotatably mounted on a pin or shaft I98 that extends between and projects through the legs of the link. To insure a minimum of frictional resistance to rotation of the roller 87 on the pin I08, the roller may comprise a dust-sealed ball bearing having an inner race surrounding the pin I98 with a tight t and an outer race constituting the rim of the roller. The pin I08 projects laterally a short distance beyond each side of the link I96 (Fig. 5)

F to provide anchorages for the upper ends of a pair of helical springs I09 that are held under tension. Each projecting portion of the pin I08 is provided with a circumferential groove III adapted to receive a loop on the upper end of the associated spring, similar loops on the lower ends of both springs bein held in similar circumferential grooves II2 provided in the shaft 82 on which the valve-actuating lever is mounted.

With the above described linkage acting between the large diaphragm 38 and the roller 81, and with the roller in the position shown in Fig. 2, upward movement of the diaphragm 38 in response to an increase in the pressure within the upper pressure compartment 43 will cause the lever I0!) to swing counterclockwise (as viewed in Figs. 2 and 3) about its fulcrum shaft Hi2 and will cause the roller 81 to roll along the cam surface 85 of the valve-actuating lever SI toward the cam surface 86 thereof. Continued upward movement of the large diaphragm 38 will eventually permit the roller, moving under the influence of the two springs I89, to be suddenly rolled downwardly along the. cam surface 85, thereby forcing the lever 8| to swing rapidly clockwise (as viewed in Figs. 2 and 3) about its fulcrum shaft 82 and to force the movable valve element 68 into valve closing engagement with the valve seat 62 on the block 51. In this position (shown in Fig. 3), the movable valve eleface at any given instant.

ment interrupts communication between'the con element 68 to move to the left into engagement with the seat I2 on the bushing II. Because of the tension inthe springs I63, the roller 81 bears forcibly on the cam surface 86 regardless of where the roller may be positioned along this sur- Consequently, the lever 8| is held in the position shown in Fig. 3 all during the upward travel of the roller along this surface toward the intersectin surface 85, and will not be permitted to swing out of that position until the roller has actually rolled onto the surface 8 5.

The pressure in the upper pressure compartment 43 that is required to move the roller 81 from the inoperative position shown in Fig. 2 to the operative position shown in Fig. 3 is supplied through the conduit 23 that connects the upper pressure compartment to the reservoir 22. The magnitude of the pressure required for this purpose is determined by an adjustable springloaded device housed within the air compartment 46. As best shown in Figs. 2 and 4, this device includes a pivot pin H3 having a shank portion 'of reduced diameter that fits loosely into the upper end of the hollow upper shank 82 of the diaphragm stud. The upper end of the pivot pin H3 is tapered to a knife edge adapted to bear against the lower surface of a lever arm II4 that projects radially from the center of a horizontally disposed spindle H6. The spindle H6 is provided at its opposite ends with a pair of enlarged, integrally formed hubs II'I that are drilled or bored to receive, respectively, the outer races of a pair of ball bearings II8. The inner races of the ball bearings H8 are respectively mounted on a pair of male trunnions II!) that are threaded into opposite sides of the upper casting 3!. Each of the hubs III on the spindle II6 is provided with a generally upwardly-extending, integrally-fcrmed-crank arm I2I, and a shaft I22 extends between and is suitably mounted at its opposite ends in the crank arms I2I. Between the crank arms I2I, the shaft I22 I is surrounded by a number of sleeves I23 that are slightly spaced-apart along the shaft toprovide, in effect, a plurality'of circumferential grooves therebetween that are adapted to receive and position loops in the ends of a corresponding plurality of helical springs I24, by means of which a selected torque may be applied to the spindle II6 for urging the lever arm II4 downwardly against the knife edge of the pivot pin I I3.

The helical springs I24 are held under a selected tension that is manually adjustable while the valve is in service without interrupting its op pair of cars I30 that extend upwardly into 'close' proximity with the top of the upper casting 3I for preventing tilting of the crosshead in case the springs I24 are not properly balanced. At its center the crosshead is provided with an aperture I3I through which a longitudinally movable, horizontal shaft I32 is projected. The distance the shaft I32 may project through-the aperture I3I in the crosshead is limited by a stop I33 on the shaft I32, which stop may conveniently comprise a circumferential shoulder formed by a change in the diameter of the shaft at that point along its length. The portion of the shaft I32 that projects through and beyond the crosshead I28 is mounted in a cap or bearing I34 that is threaded into the upper casting 3|,the cap being long enough for the shaft I32 to slide a substantial distance into the cap. The opposite end of the shaft I32 projects with clearance into a long, hollow boss I36, formed integrally with the upper casting 3i, andter minates within the boss. This end of the shaft is drilled or bored to provide a socket I3l adapted to receive a tip I38 of slightly smaller diameter on the end of the threaded shank of a wing;

screw I39, the boss I36 being internally threaded to accommodate the wing screw. For convenience, the boss I36 may be projected through a suitable aperture in the supporting panel 49 to facilitate mounting the valve unit on the panel.

A longitudinally extending groove MI is -cut into the threaded shank of the wing screw to provide an air passage into the air compartment 36 for maintaining atmospheric pressure therein at all times, and a cotter pin I42, or the like, is passed through the shaft I32 at an appropriate point along the length of the shaft to provide a stop for limiting the distance the shaft can be moved into the boss I36. 7

By rotating the wing screw I33 in one direction,

the shaft I32 is caused to move longitudinally to theright (as viewed in Fig. 2), thereby increasing the tension in the helical springs I24 and the downward force exerted upon the large diaphragm 38. Similarly, by reversing the rotation of the wing screw I39, the shaft I32 is permitted to slide in the opposite direction under the influence of the springs I24, and the downward force exerted upon the large diaphragm 38 is decreased. In this manner ,the magnitude of the gas pressure in the upper pressure compartment 43 required to move the large diaphragm 38" upwardly for causing the movable valve element 68 to interrupt communication between the conduits 21 and 23, in the manner described above, may be manually adjusted while the valve is in service without interrupting its operation.

While the particular embodiment of the invention disclosed herein employs a spring-loaded mechanism for loading the large diaphragm 38, it is obvious that the same end result could be accomplished in other ways. Fig. 7 illustrates one such alternative. The compartment 46 is closed to the atmosphere except for the small bleed hole IIIl. Air or gas under pressure is introduced to the compartment 46 through the pressure regulator I'II adjacent the inlet tube I'I2. By this means, a regulated gas pressure is maintained in the compartment 46 for controlling the range of operating pressurein the upper pressure compartment 43. Where this range of operating pressures is relatively high (7 or S lbs/sq. in. and above) such an expedient maybe superior to the one illustrated'in Figs. 2 to 6 and described above because the balancing of pressures on opposite sides of the large diaphragm results in lower diaphragm stresses. However, with alower range of operating pressures, or whenever'forany other reasonthe diaphragm stresses encountered are not of any greatzconcerma valve unit employ ing a spring-loaded mechanism for loading the. large diaphragm 38 is preferred becausethe gas system required is less complicated: and less expensive to install and maintain.

After the roller. 81 has. moved: from its inoperative position (shown in Fig. 2) to its operative position (shown in Fig. 3) inwhich it holds the movable valve element 68 againstthe valve seat.

62, a considerable drop-intherpressurewithirr the upper pressure compartment 43 would normally be required to force therolier back uplthe cam surface 86 to its inoperative positionon the cam surface 85 for restoring communication between the conduits 21 andv 23. In: order to accomplish.

therefrom. Another short: rod I46, larger indi ameter than the rod I44,,isdrillediongitudinally from one end fora distancevsufilcienttc' accommodate the pin I44 therein. andiis longitudinally slotted atitsl opposite end to form. a pair'of'up wardly projecting, spaced-apart ears I41'between which one end of a bell crank I50 is'pivotally connectedby means of'a pinII- The bell crank I 50 may be mounted with a pressedfit on the center of the fulcrum shaft I02,midwaybetween the arms 990i the lever I00. The opposite end of the bell crank I50 is disposedbetween apair of spaced-apart ears I52 that project from one end of a. generally horizontally disposed link I53, and a pin I54 pivotally connects thisrend of the bell crank to the ears I52. The. pin I54 projects through both of the ears I52 and beyondthem in each direction (as. shown in .4) so'that the ends of the pin" will respectively bear against a pair of inwardlyprojecti'ng lugs: provided for that purpose on the two arms 991'of1therlevertI00 when the bell crank I50. isin the position shown in Fig. 3, thereby urging the lever I100 in a clockwise direction (as viewed in Figs. 2and"3) about its fulcrum shafti02' for assisting returnzof: the roller 81 to its inoperative position shown in Fig. 2'.

The link I53 projects into ahollow boss I56,

formed integrally withthe lower casting 32, and

terminates inside the boss I55 in a flanged seat I51 adapted. to receive oner end of a helical compression, spring I58. that is housed within the boss I56. A portionofthelength of the boss l56 is internally threaded,v and an externallythreaded plug or screw I59, having a seat I'GI-for the opposite end of the spring I58, is screwedinto the boss for subjecting. thesprin'gitoiaselected, adjustable degree. of compression betweenthe screw I59 and the link. I53, To insure against leakage of gas from, the-upper pressure compartment 43, a secondplug I62; havingza suitable washer or gasket I03 associated therewith, is screwed snugly into the outer end of the boss: I561 The plug I62 may readily be removectwhile the valve is in operation inorder: to. give" access; to the screw I59 for adjustin the" stressxin the spring I58,.

At appropriate timest as: described hereinafter;

10 the force exerted on the small diaphragm 42 by the diaphragm plate I43, as determined by the compression of the spring I58, is opposed by gas pressure within the lower pressure compartment 44. lower pressure compartment 44 for this purpose, and is subsequently exhausted therefrom, through a small passageway I64 drilled through the closure disk 39 and communicating at its opposite ends with the valve. outlet port 63 and with the" lower pressure compartment 44, respectively. When the movable valve element 58 is seated against the seat 62 on the block51, as shown in.

Fig. 3, the valve chamber 54, the outlet port 63, and the lower pressure compartment 44' are serially in communication with the upper pressure compartment through. the port 80. in the 'bush- Under these conditions, the pressure in ing H. the lower pressure compartment 44 is substantially the same. as that in the upper pressure compartment 43, and the small diaphragm 42 exerts 'no force on the bell crank mechanism in opposition to the force exerted thereon by the' compression spring I58. Consequently, the force exerted by thespring I58 is transmitted through the ends of' the pin I54 to the arms 99 of the lever I00, thereby urging the lever I00 in a clockwise direction (as viewed in Figs. 2 and 3) about the fulcrum shaft I02 in opposition to the mo ment applied thereto as a result of the tension in the two springsv I09. r

When the pressure in the upperpressure compartment 43 drops suificiently'for the large diaphragm 38 to move downwardly and, with the duits 21 and 23 is restored; Whenthis occurs,- communication between the upper pressure compartment 43 andthe'valve chamber 54 is cut off;

and thepressure within the conduit 21 is transmitted'through the outlet port and'the passageway I64: into thelower pressure compartment 44. The small diaphragm 42 is forced upwardly by this pressure, thereby turning the bell crank I50lcounterclockwise (as viewed in Figs. 2 and 3), in opposition to the force. exerted by the spring I58, for disengaging the bell crank mechanism from the lever I00 and rendering the spring I58 inoperative. Under these conditions, a relatively small increase in the pressure Withinthe upper pressure compartment 43 (determined by the ad'- justable tension in the springs I24) moves the large diaphragm 38 upwardly and again interrupts communication between the conduits 21 and 23 in theimannerdescribed above, restoringthe valve actuating mechanism to the condition shown in Fig; 3'.

By adjustment of the position of the screw I59 along the length of the threaded portion of the boss I56, the force exerted by the compression spring I58 can be varied for selecting the pressure drop within the upper pressure compartment 43 to which the valve-actuating mechanism will respond. for moving the roller 81 back to its inoperative position shown in Fig. 2. The greater the forceexerted by the spring I58, the higher Will bethe minimum pressure withinthe upper pressure compartment; and vice versa. Also, as described above, by adjustment of the wing screw I39, the pressure in. the: upper pressure compartment required torrmove' the roller 81 from its inopera- Gas under pressure is admitted into the' i1. tive position shown in Fig. 2 to its operative posi tion shown in Fig. 3 may be selectively varied. Thus,;while the valve is in service, and without interrupting its operation, the maximum and minimum pressures in the upper pressure compartment 43 towhich the valve-actuating mechanism responds may be individually or jointly raised or lowered for maintaining a selected'average pressure in the reservoir 22 with a selected degree of variation from the average.

The selected maximum pressure to be reached within the upper pressure compartment is determined entirely (neglecting friction in the valveactuating mechanism) by the force exerted by the springs I24. To permit a wide range of maximum pressures to be selected, the shafts I22 and I26 maybe coupled by any desired number of springs I24 (within obvious physical limits) when the valve is assembled for any particular type of service, only changes in the length and number of spacer sleeves I23 and I29 being required. Since the compression spring I58 merely opposes the two springs I69 for reducing the diiference between the maximum and minimum valve operating pressures, a change in the number of springs I24 employed for loading the large diaphragm 38 does not require a corresponding change in the strength of the compression spring I58." 7

Referring now to the operation of the valve unit shown in Figs. 2 to 6 with particular reference to the manner in which it functions when employed in the gas system schematically shown in Fig. 1, it will first be assumed that the movable valve element 68 is seated against the seat 12 on the bushing II so that the conduits 21 and 23 are in communication with each other through the valve chamber 54. Under such circumstances, the above described valve-actuating mechanism is in the-condition shown in Fig. 2, and the pressure in the conduit 23 holdsthe distributor I2 in its on condition for supplying a. continuous, uniform fiow of butane gas to the'mixer I6, within which air'is mixed with the butane and from which the resulting gas mixture is supplied to V the reservoir 22 through the Venturi tube 2|. As

the pressure in the reservoir 22 rises, a corresponding rise in the pressure within the upper pressure compartment 43 of the valve unit occurs because of its communication with the reservoir 22 through theconduit 29. As the pressure within the upper pressure compartment 43 approaches a preselected maximum value, determined by the tension applied to the springs I24, the large diaphragm 38 moves upwardly in opposition to the force exerted by the springs I24; and, when the pre-selected maximum pressure is reached, the roller 87 is at the intersection of the cam surfaces 85 and 86 on the valve-actuating lever 8| Any further increase in this pressure will move the roller 81 far enough for the springs I09 to pull it downwardly along the cam surface 86; thereby actuating the valve with a snap action by quickly moving the movable valve element 68 into engagement with the seat 62 on the block 51 and interrupting communication between the conduits 21 and 23. The pressure in' the conduit 23 and in the lower pressure compartment 44 then immediately drops to the pressure within the upper pressure compartment 43, thereby permitting the small diaphragm 42 to move downwardly, at which time the valve-actuating mechanism is in the condition shown in Fig.

3. The drop in pressure within the conduit 23 releases the distributor I2 to its ofi" condition,

thereby stopping the supply of mixed-gas to the reservoir 22. As mixed gas is drawn from the reservoir 22 by whatever gas consuming equipment it supplies, the pressure within the upper pressure compartment 43 undergoes a corresponding drop. As this occurs, the combined forces exerted by the spring orsprings I24 and by the spring I58 cause the'largediaphragm 38 to move downwardly and the rollerB'I to move along the cam surface 86 toward the cam surface 85. The pressure drop within the .upper pressure compartment 43 required to move the roller 87 upwardly again to the intersection of the cam surfaces and 86 depends upon the pre-selected compression applied to the spring I58 by the screw I59. When the predetermined pressure drop is exceeded, the roller 87 rolls onto the cam surface 85, and the pressure in the conduit 27 forces the movable valve element 68 quickly into engagement with the seat I2 on the bushing II, thereby restoring communication between the conduits 2'! and 23, actuating the distributor I2 back to its on condition for supplying butane to the mixer I6, raising the pressure within the lower pressureicompartment 44, and restoring the valve-actuating mechanism' to the condition shown in Fig. 2; I

From the foregoing detailed description of a.

preferred embodiment of a valve constructed in "accordance with the'present invention, together tended that the appended claims shall cover all such modifications of the described structure as fall withina reasonable construction of the terms employed in the claims.

I claim:

1. A snap-acting 'valve for opening and closing'a first conduit in response to changes in fluid pressure in a second conduit, comprising a housing defining a chamberclosed'at one end by a first flexible diaphragmand divided into first and second compartments by a second flexible diaphragm, a port communicating with said first V compartment and adapted to beconnected to said second conduit, amovable valve element adapted to be interposedin said first conduit for open-.

ingand closing the same, said movable valve element having a valve stem projecting into said first compartment, first means movable between operative and inoperative positions in response to movement of said first diaphragm and being adapted in its operative position to apply a valve closing'force to said valve stem, a first spring associated with said first means for urging it toward its operativeposition, a, second spring associated with said first means for urging it toward its inoperative position, and second means operative in response to movement of said second dia phragm for ative.

2. A snap-acting valve for opening and closing afirst conduit in response to changes in'fluid pressure in a second conduit, comprising a hous-' rendering said second spring inoperand second compartments by a second flexible diaphragm, a port communicating with said first compartment and adapted to be connected to said second conduit, a movable valve element adapted to be interposed in said first conduit for opening and closing the same, said movable valve element having a valve stem projecting into said first compartment, first means movable between operative and inoperative positions in response to movement of said first diaphragm and being adapted in its operative position, to apply a valve closing force to said valve stem, a first spring associated with said first means for urging it toward its operative position, a second spring associated with said first means for urging it towardv its inoperative position, and second means acting between said second diaphragm and said second spring for rendering said second spring inoperative in response to a pressure increase in said second compartment.

3. A snap-acting valve for opening and closing a first conduit to fluid flow from a high-pressure end to a low-pressure end thereof, comprising a housing defining a chamber closed at one end by a first flexible diaphragm and divided into first and second compartments by a second flexible diaphragm, a port communicating with said, first compartment and adapted to beconnected to said second conduit, a port communicatingwith said second compartment and adapted to be connected to said first conduit adjacent the low-pressure end thereof, a movable valve element adapted. to be interposed in said first conduit between the high and low-pressure ends thereof for opening and closing the first conduit, said movable valve 1" element having a valve stem projecting into said first compartment, first means movable between operative and inoperative positions in response to movement of said first diaphragm and. being adapted in its operative position to apply a valveclosing force to said valve stem, a first spring associated with said first means forurging it toward its operative position, a secondspring associated with said first means for urging it toward its inoperative position, and second means acting between said second diaphragm and said second spring for rendering said second spring inoperative in response to a pressure increase in said second compartment.

4. A snap-acting valve for opening and closing av high-pressure conduit in response to changes in pressure in a low-pressure conduit, comprising a housing defining a chamber, a first flexible diaphragm closing one end of said chamber, a second flexible diaphragm dividing said chamber into first and second compartments, a port communicating with said first compartment and adapted to be connected to said low-pressure conduit, a movable valve element mounted on said housing and adapted to be interposed in said high-pressure conduit, said valve element having a valve stem projecting into said first compartment, first means movable between operative and inoperative positions in response to movement of said first diaphragm and being adapted in its operative position to apply a valve-closing force to said valve stem, a first spring associated with said first means for urging it toward its operative position, a second spring associated with said first means for urging it toward its inoperative position, second means acting between said second diaphragm and said second spring for rendering said second spring inoperative in response to a pressure increase in said second compartment, and means for subjecting said second com- All ill

14 partment to the pressure in said high-pressure conduit when the latter is open for fluid flow therethrough.

5. A snap-acting valve for opening and closing a first conduit in response to changes in fluid pressure in a second conduit, comprising a housing defining a chamber closed at one end by a first flexible diaphragm and divided into first and second compartments by a second flexible diaphragm, a port communicating with said first compartment and adapted to be connected to said second conduit for subjecting said diaphragms to a variable pressure within said first compartment, mechanism mounted on said housing for adjusting the resistance of said first diaphragm to said variable pressure, a movable valve element adapted to be interposed in said first con duit for opening and closing the same, said movable valve element having a valve stem projecting into said first compartment, first means movable between operative and inoperative positions in response to movement of said first diaphragm and being adapted in its operative position to apply a valve-closing force to said valve stem, a first spring associated with said first means for urging it toward its operative position, a second spring associated with said first means for urging it toward its inoperative position, second means acting between said second diaphragm and said second spring for rendering said second spring inoperative in response to a pressure increase in said second compartment, and means for subjecting said second compartment to a pressure increase when, said first conduit is open for fluid flow therethrough.

6. A snap-acting valve for opening and closing a first conduit in response to changes in fluid pressure in a second conduit, comprising a housing defining a chamber closed at one end by a first flexible diaphragm and divided into first and second compartments by a. secnod flexible diaphragm, a port communicating with said first compartment and adapted to be connected to said second conduit for subjecting said diaphragms to a variable pressure within said first compartment, a movable valve element adapted to be interposed in said first conduit for opening and closing the same, said movable valve element having a valve stem projecting into said first compartment, first means movable between operative and inoperative positions in response to movement of said first diaphragm and being adapted in its operative position to apply a valve-closing force to said valve stem, a first spring associated with said first means for urging it toward its operative position, a second spring associated with said first means for urging it toward its inoperative position, mechanism mounted on said housing for adjusting the force exerted by said second spring on said first means, second means acting between said second diaphragm and said second spring for rendering said second spring inoperative in response to a pressure increase in said second compartment, and means for subjecting said second compartment to a pressure increase when said first conduit is open to fluid flow therethrough.

7. A snap-acting valve for opening and closing a first conduit in response to changes in fluid pressure in a second conduit, comprising a housing defining a chamber closed at one end by a first flexible diaphragm and divided into first and second compartments by a second flexible diaphragm, a port communicating with said first compartment and adapted to be connected to said second conduit for subjecting said 'diaphragms to a variable pressure within said first compartment, mechanism mounted on said housing for adjusting the resistance of said first diaphragm to said variable pressure, a movable valve element adapted to be interposed in said first conduit for opening and closing the same, said movable valve element having a valve stem projecting into said first compartment, first means movable between operative and inoperative positions in response to movement of said first diaphragm and being adapted in its operative position to apply a valve-closing force to said valve stem, a first spring associated with said first means for urging it toward its operative position, a second spring associated with said first means for urging it toward its inoperative position, mechanism mounted on said housing for adjusting the force exerted by said second spring on said first means, and second means acting between said second diaphragm and said second spring for rendering said second spring inoperative in response to a pressure increase in said second compartment, and means for subjecting said second compartment to a pressure" increase when said first conduit is open for fluid flow therethrough.

8. A snap-acting valve for opening and closing a first conduit in response to changes in fluid pressure in a second conduit, comprising a housing defining a chamber closed at one end by a first flexible diaphragm and divided into first and second compartments by a second flexible diaphragm, a port communicating with said first compartment and adapted to be connected to said second conduit for subjecting said diaphragm; to a variable pressure within said first compartment, said housing also defining a valve chamber adapted to be interposed in said first conduit and including an inlet and an outlet port permitting fluid fiow therethrough, a movable valve element disposed in said valve chamber for opening and closing the valve chamber to fluid fiow therethrough, said movable valve element having a valve stem projecting into said first compartment, first mean movable between operative and inoperative positions in response to movement of said first diaphragm and being adapted in its operative position to apply a valveclosing force to said valve stem, a first spring associated with said first means for urging it toward its operative position, a second spring associated with said first means for urging it toward its inoperative position, second means acting between said second diaphragm and said second spring for rendering said second spring inoperative in response to a pressure increase in said second compartment, and a conduit connecting said outlet port with said second compartment for controlling the pressure in the latter.

9. A snap-acting valve for opening and closing a first conduit in response to changes in fluid pressure in a second conduit, comprising a housing defining a chamber closed at one end by a first flexible diaphragm and divided into first and second compartments by a second flexible diaphragm, a port communicating with the first compartment of said chamber and adapted to be connected to saidsecond conduit for subjecting said diaphragms to a variable pressure within said first compartment, mechanism mounted on said housing ,for adjusting the resistance of'said first diaphragm to said variable pressure, said housing also defining a valve chamber adapted to be interposed in said first conduit and including an inlet and an outlet port permitting fluid fiow therethrough, a mov able valve element disposed in said valve chamber for opening and closing the valve chamber to fluid fiow therethrough, said movable valve element having a valve stem projecting into said first compartment, first means movable between operative and inoperative positions in response to movement of said first diaphragm and being adapted in its operative position to apply a valveclosing force to said valve stem, a first spring associated with said firstmeans for urging it toward its operative position, a second spring associated with said first means for urging it toward its inoperative position, second means acting between said second diaphragm and said second spring for rendering said second spring inoperative in response to a pressure increase in said second compartment, and a conduit connecting said outlet port with said second compartment 'for controlling the pressure in the latter. V

10. A snap-actingvalve for opening and closing a first conduit in response to changes in fluid pressure in a second conduit, comprising a housing defining a chamber closed at one end by a first flexible diaphragm and divided into first and second compartments by a second flexible diaphragm, a port communicating with said first compartment and adapted to be connected to said second conduit for subjecting said. diaphragms to a variable pressure within said first compartment, said housing also defining a valve chamber adapted to be interposed in said first conduit and including an inlet and an outlet port permitting'fluid flow therethrough, a movable valve element disposed in said valve chamber for opening and closing the valve chamber to fluid flow therethrough, said movable valve element having a valve stem projecting into said first compartment, first means movable between operative and inoperative positions'in response to movement of said first diaphragm and being adapted in its operative position to apply a valve-closing force to said valve stem, a first spring associated with said first means for ur ing it toward its operative position, a second spring associated with said first means for urging it toward its inoperative position, mechanism mounted on said housing for adjusting the force exerted by said second spring on said first means, second means acting between said second diaphragm and said second spring 'for rendering said second spring inoperative in response to a pressure increase in said second compartment, and a conduit connecting said outlet port with said second compartment for controlling the pressure in the latter.

11. A snap-acting valve for opening and closing a first conduit in response to changes in fluid pressure in a second conduit, comprising a housing defining a chamber closed at one end by a first flexible diaphragm and divided into first and second compartments by a second flexible diaphragm, a port communicating with said first compartment and adapted to be connected to said second conduit for subjecting said diaphragms to a variable pressure within said first compartment, mechanism mounted on said housing for adjusting the resistance of said first diaphragm to said variable pressure, said housing also defining a valve chamber adapted to be interposed in said first conduit and including an inlet and an outlet port permitting fluidrflow therethrough, a movable valve element disposed in said valve chamber for opening and closing the valve chamber to fluid flow therethrough, said movable valve element having a valve stem projecting into said first compartment, first means movable between operative and inoperative positions in response to movement of said first diaphragm and being adapted in its operative position to apply a valve closing pressure to said valve stem, a first spring associated with said first means for urging it toward its operative position, a second spring associated with said first means for urging it toward its inoperative position, mechanism mounted on said housing for adjusting the force exerted by said second spring on said first means, second means acting between said second diaphragm and said second spring for rendering said second spring inoperative in response to a pressure increase in said second compartment, and a conduit connecting said outlet port with said second compartment for controlling the pressure in the latter.

12. Valve-actuating mechanism comprising a frame, a lever pivotally mounted on said frame and having a cam surface thereon, cam-actuating means mounted on said frame and including a roller mounted for movement along said cam surface between operative and inoperative positions with respect thereto and pressure-responsive means for controlling the position of said roller along said cam surface and yieldable means urging said roller toward said cam surface and toward an operative position with respect thereto, means for adjusting said pressure-responsive means for varying the pressures to which it is responsive, and additional yieldable means for urging said roller along said cam surface toward an inoperative position against the action of said first-named yieldable means.

13. Valve-actuating mechanism comprising a frame, a lever pivotally mounted on said frame and having a cam surface thereon, cam-actuating means mounted on said frame and including a roller mounted for movement along said cam surface between operative and inoperative positions with respect thereto and pressure-responsive means for controlling the position of said roller along said cam surface and yieldable means for urging said roller toward said cam surface and toward an operative position with respect thereto, means for adjusting said pressure-responsive means for varying the pressures to which it is responsive, additional yieldable means for urging said roller along said cam surface toward an inoperative position against the action of said first-named yieldable means, means for adjusting said additional yieldable means for varying the force applied thereby to said roller, and additional pressure-responsive means for rendering said additional yieldable means inoperative.

14. Valve-actuating mechanism comprising a frame, a lever pivotally mounted on said frame and having a cam surface thereon, cam-actuating means mounted on said frame and including a roller mounted for movement along said cam surface between operative and inoperative positions with respect thereto and pressure-responsive means for controlling the position of said roller along said cam surface and a first spring for urging said roller toward said cam surface and toward an operative position with respect thereto, means for adjusting said pressure-responsive means for varying the range of pressures to which it is responsive, a second spring for urging said roller along said cam surface toward an inoperative position against the action of said first spring, and additional pressure-responsive means for rendering said second spring inoperative.

15. Valve-actuating mechanism comprising a frame, a lever pivotally mounted on said frame and having a cam surface thereon, cam.-actuating means mounted on said frame and including a roller mounted for movement along said cam surface between operative and inoperative positions with respect thereto and pressure-responsive means for controlling the position of said roller along said cam surface and a first spring for urging said roller toward said cam surface and toward an operative position with respect thereto, means for adjusting said pressure-responsive means for varying the range of pressures to which it is responsive, a second spring for urging said roller along said cam surface toward an inoperative position against the action of said first spring, and additional pressure-responsive means for rendering said second spring inoperative, said second spring being adjustable to vary the force applied thereby to said roller.

16. Valve-actuating mechanism comprising a housing defining a chamber closed at one end by a first flexible diaphragm and divided into first and second compartments by a second flexible diaphragm, a valve-actuating cam, camoperating means movable between operative and inoperative positions in response to movement of said first diaphragm, first yieldable means urging said cam-operating means toward said cam and toward an operative position with respect thereto, and second yieldable means operative in response to movement of said second diaphragm for opposing the action of said first yieldable means.

17. Valve-actuating mechanism comprisinga housing defining a chamber closed at one end by a first flexible diaphragm and divided into first and second'compartments by a second. flexible diaphragm, a lever pivotally mounted on said housing and having a cam surface thereon, lever-actuating means mounted on said housing and including a roller mounted for movement along said cam surface between operative and inoperative positions with respect thereto and a first spring for urging said roller toward said cam surface and toward an operative position with respect thereto, said lever-actuating means being associated with said first diaphragm for controlling the position of said roller with respect to said cam surface in response to variations in pressure within said first compartment, and a second spring associated with said second diaphragm for urging said roller toward an inoperative position with respect to said cam surface in response to a drop in pressure within said second compartment.

18. Valve-actuating mechanism comprising a housing defining a chamber closed at one end by a first flexible diaphragm and divided into first and second compartments by a second flexible diaphragm, a lever pivotally mounted on said housing and having a cam surface thereon, lever-actuating means mounted on said housing and including a roller mounted for movement along said cam surface between operative and inoperative positions with respect thereto and a first spring for urging said roller toward said cam surface and toward an operative position with respect thereto, said lever-actuating means being-associated with said firstldiaphragm forrcontrolling: the: position. of said. roller: with respect to said,camasurface iniresponse to; variaitionsiv in-j pressuregzwith-ins, said; first". compartment; means a: forrvarying zthearesistanoer of said first diaphragm to pressure :within: said; first compartment, and; 31151300171011 springs; associated with-=v said; second; diaphragm: for; urging; said roller toward; :aninoperative position withre:- spectzito said: cam surfaceinrresponseatoa; drop I in; pressuregwithinsaid-second compartment..

19. Valvefactuating -mechanism; comprisin a housing. defining a chamber closed at.;one: end bye-afirst; flexible: diaphragrnqand" divided into firstnandsecond-compartments by; a second-flexible diaphrag;m-, a; lever pivotally; mounted on saidzhousing andihaving at cam surface-thereon, lever-actuating 'meansamounted onysaid housing anda-including; a; roller mountedqforpmovement along; said; cam surface between; operativeand inoperative positions with. respect-thereto=,and.-a firstsspring fon urgingv said roller. toward?- said cam surface and toward; an: operative+ position with; respectnthereto; saidalever actuating;:means being;- associated with: said first rdiaphragm: for controlling the-position of said; roller with; respect.:-to said cam surfaceeinzresponserto variations in;; pressure with-in said first compart menti means ior varying; the resista-ncesof isaid first diaphragm? to pressurewithimsaid first compartment, 313560011611; spring associated with said; second.- diaph-ragmr. fort urging said: when toward-:an inoperative position-:with respect to saidqcam' surface -in-response1to-a drop impressure within said second: compartment, and means for varyingttheforce appliedv by said second" Spring: to said *rollen 20.: The valve claimed: in, claims, 5 in: which the? mechanism-x mounted,- onsaid housing for adjusting the resistance of said first diaphragm to :said-variablepressure comprises? adjustable spring means= exerting; tension on saidt; first diaphragm.

21; The-va-Lveeclaimed: in claim 5;. in; which the mechanism mounteda -on said. housing; for

20 adjusting theJresistancesoft. said first diaphragm to: said: variable" pressure; (30111131186558; second pressure.-.-chamber: onzthe-ppposite; side-of' said first;diaphragmafromzsaid-t-first-mentionedclosed chamber andzmeans to vary; the --pressurez;within said: -second.pressurechamben.,v

22.: The. mechanism; claimed in; claim: 12. in which the-means for adjusting; saidipressuree responsive. meansafor varying theypressuresto which. it is responsive: comprises. adjustable spring; means exerting; tension onsaidpressureresponsive means.

23. The? mechanism; claimed in; claim; 12-. in which. the means ion-adjusting; said. pressureiresponsive meansior-v varying the. pressure to which; it is responsive. comprises a; pressure chamber t on: the ioppositeesidevof said pressure.- responsive :means irom said roller. and .means; to regulate the-pressure: in said chamber;

2i. .Themechanism. claimed; in claim:v 1.8 .in which themeansifor s varying. the resistance-- of said.- first diaphragnr to;-pressure-* within said first compartment comprises adjustable spring meanss-exertingtension, against said first diaphragm.:

25.1The-mechanism claimed in claim; 18: in whichthe means? forvarying; the; resistance: of said first diaphragm to pressureawithin saidfirst compartment; comprises, a third. compartment closed, on a one end. by said; housing and on the other. end, by said firstdiaphragm; and, means-tier regulating v the pressure 6' withing, said compartmentz,

REFERENCES CITED The following references' are" of recordiinx the fil'e of this patent:

UNITED STATES LPA'IE'NTS' 7.

Number- Name, a Date 468,440.- Fortier .Ji'eb. 9', 1892 1,98,6,5,11- Mayer- Jan. 1,; 1935 2,-142;903 King" Jan. 3,- 1939 2,267,688 Landon- Dec. 23,1941 

